V4L/DVB (6731): ivtv: Remove a invalid shadow-variable

Remove the shadowing 'struct v4l2_chip_ident *chip', since it already exists
and makes the if-statement useless.

Signed-off-by: Richard Knutsson <ricknu-0@student.ltu.se>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>